memremap: add MEMREMAP_WC flag
Add a flag to memremap() for writecombine mappings. Mappings satisfied
by this flag will not be cached, however writes may be delayed or
combined into more efficient bursts. This is most suitable for buffers
written sequentially by the CPU for use by other DMA devices.
Signed-off-by: Brian Starkey <brian.starkey@arm.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/include/linux/io.h b/include/linux/io.h
index 32403b5..e2c8419 100644
--- a/include/linux/io.h
+++ b/include/linux/io.h
@@ -135,6 +135,7 @@
/* See memremap() kernel-doc for usage description... */
MEMREMAP_WB = 1 << 0,
MEMREMAP_WT = 1 << 1,
+ MEMREMAP_WC = 1 << 2,
};
void *memremap(resource_size_t offset, size_t size, unsigned long flags);